From e482f9590f2e831c68bcf85e3f9f4c88bbd3329f Mon Sep 17 00:00:00 2001
From: Sean Wang <sean.wang@mediatek.com>
Date: Mon, 20 Mar 2017 14:47:26 +0800
Subject: [PATCH 20/57] leds: Add LED support for MT6323 PMIC

MT6323 PMIC is a multi-function device that includes LED function.
It allows attaching up to 4 LEDs which can either be on, off or dimmed
and/or blinked with the controller.

Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
---
 drivers/leds/Kconfig       |   8 +
 drivers/leds/leds-mt6323.c | 502 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 510 insertions(+)
 create mode 100644 drivers/leds/leds-mt6323.c

--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -117,6 +117,14 @@ config LEDS_MIKROTIK_RB532
 	  This option enables support for the so called "User LED" of
 	  Mikrotik's Routerboard 532.
 
+config LEDS_MT6323
+	tristate "LED Support for Mediatek MT6323 PMIC"
+	depends on LEDS_CLASS
+	depends on MFD_MT6397
+	help
+	  This option enables support for on-chip LED drivers found on
+	  Mediatek MT6323 PMIC.
+
 config LEDS_S3C24XX
 	tristate "LED Support for Samsung S3C24XX GPIO LEDs"
 	depends on LEDS_CLASS
--- /dev/null
+++ b/drivers/leds/leds-mt6323.c
@@ -0,0 +1,502 @@
+/*
+ * LED driver for Mediatek MT6323 PMIC
+ *
+ * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/mfd/mt6323/registers.h>
+#include <linux/mfd/mt6397/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/*
+ * Register field for MT6323_TOP_CKPDN0 to enable
+ * 32K clock common for LED device.
+ */
+#define MT6323_RG_DRV_32K_CK_PDN	BIT(11)
+#define MT6323_RG_DRV_32K_CK_PDN_MASK	BIT(11)
+
+/*
+ * Register field for MT6323_TOP_CKPDN2 to enable
+ * individual clock for LED device.
+ */
+#define MT6323_RG_ISINK_CK_PDN(i)	BIT(i)
+#define MT6323_RG_ISINK_CK_PDN_MASK(i)	BIT(i)
+
+/*
+ * Register field for MT6323_TOP_CKCON1 to select
+ * clock source.
+ */
+#define MT6323_RG_ISINK_CK_SEL_MASK(i)	(BIT(10) << (i))
+
+/*
+ * Register for MT6323_ISINK_CON0 to setup the
+ * duty cycle of the blink.
+ */
+#define MT6323_ISINK_CON0(i)		(MT6323_ISINK0_CON0 + 0x8 * (i))
+#define MT6323_ISINK_DIM_DUTY_MASK	(0x1f << 8)
+#define MT6323_ISINK_DIM_DUTY(i)	(((i) << 8) & \
+					MT6323_ISINK_DIM_DUTY_MASK)
+
+/* Register to setup the period of the blink. */
+#define MT6323_ISINK_CON1(i)		(MT6323_ISINK0_CON1 + 0x8 * (i))
+#define MT6323_ISINK_DIM_FSEL_MASK	(0xffff)
+#define MT6323_ISINK_DIM_FSEL(i)	((i) & MT6323_ISINK_DIM_FSEL_MASK)
+
+/* Register to control the brightness. */
+#define MT6323_ISINK_CON2(i)		(MT6323_ISINK0_CON2 + 0x8 * (i))
+#define MT6323_ISINK_CH_STEP_SHIFT	12
+#define MT6323_ISINK_CH_STEP_MASK	(0x7 << 12)
+#define MT6323_ISINK_CH_STEP(i)		(((i) << 12) & \
+					MT6323_ISINK_CH_STEP_MASK)
+#define MT6323_ISINK_SFSTR0_TC_MASK	(0x3 << 1)
+#define MT6323_ISINK_SFSTR0_TC(i)	(((i) << 1) & \
+					MT6323_ISINK_SFSTR0_TC_MASK)
+#define MT6323_ISINK_SFSTR0_EN_MASK	BIT(0)
+#define MT6323_ISINK_SFSTR0_EN		BIT(0)
+
+/* Register to LED channel enablement. */
+#define MT6323_ISINK_CH_EN_MASK(i)	BIT(i)
+#define MT6323_ISINK_CH_EN(i)		BIT(i)
+
+#define MT6323_MAX_PERIOD		10000
+#define MT6323_MAX_LEDS			4
+#define MT6323_MAX_BRIGHTNESS		6
+#define MT6323_UNIT_DUTY		3125
+#define MT6323_CAL_HW_DUTY(o, p)	DIV_ROUND_CLOSEST((o) * 100000ul,\
+					(p) * MT6323_UNIT_DUTY)
+
+struct mt6323_leds;
+
+/**
+ * struct mt6323_led - state container for the LED device
+ * @id:			the identifier in MT6323 LED device
+ * @parent:		the pointer to MT6323 LED controller
+ * @cdev:		LED class device for this LED device
+ * @current_brightness: current state of the LED device
+ */
+struct mt6323_led {
+	int			id;
+	struct mt6323_leds	*parent;
+	struct led_classdev	cdev;
+	enum led_brightness	current_brightness;
+};
+
+/**
+ * struct mt6323_leds -	state container for holding LED controller
+ *			of the driver
+ * @dev:		the device pointer
+ * @hw:			the underlying hardware providing shared
+ *			bus for the register operations
+ * @lock:		the lock among process context
+ * @led:		the array that contains the state of individual
+ *			LED device
+ */
+struct mt6323_leds {
+	struct device		*dev;
+	struct mt6397_chip	*hw;
+	/* protect among process context */
+	struct mutex		lock;
+	struct mt6323_led	*led[MT6323_MAX_LEDS];
+};
+
+static int mt6323_led_hw_brightness(struct led_classdev *cdev,
+				    enum led_brightness brightness)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	u32 con2_mask = 0, con2_val = 0;
+	int ret;
+
+	/*
+	 * Setup current output for the corresponding
+	 * brightness level.
+	 */
+	con2_mask |= MT6323_ISINK_CH_STEP_MASK |
+		     MT6323_ISINK_SFSTR0_TC_MASK |
+		     MT6323_ISINK_SFSTR0_EN_MASK;
+	con2_val |=  MT6323_ISINK_CH_STEP(brightness - 1) |
+		     MT6323_ISINK_SFSTR0_TC(2) |
+		     MT6323_ISINK_SFSTR0_EN;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON2(led->id),
+				 con2_mask, con2_val);
+	return ret;
+}
+
+static int mt6323_led_hw_off(struct led_classdev *cdev)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	status = MT6323_ISINK_CH_EN(led->id);
+	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
+				 MT6323_ISINK_CH_EN_MASK(led->id), ~status);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(100, 300);
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
+				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
+				 MT6323_RG_ISINK_CK_PDN(led->id));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static enum led_brightness
+mt6323_get_led_hw_brightness(struct led_classdev *cdev)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	ret = regmap_read(regmap, MT6323_TOP_CKPDN2, &status);
+	if (ret < 0)
+		return ret;
+
+	if (status & MT6323_RG_ISINK_CK_PDN_MASK(led->id))
+		return 0;
+
+	ret = regmap_read(regmap, MT6323_ISINK_EN_CTRL, &status);
+	if (ret < 0)
+		return ret;
+
+	if (!(status & MT6323_ISINK_CH_EN(led->id)))
+		return 0;
+
+	ret = regmap_read(regmap, MT6323_ISINK_CON2(led->id), &status);
+	if (ret < 0)
+		return ret;
+
+	return  ((status & MT6323_ISINK_CH_STEP_MASK)
+		  >> MT6323_ISINK_CH_STEP_SHIFT) + 1;
+}
+
+static int mt6323_led_hw_on(struct led_classdev *cdev,
+			    enum led_brightness brightness)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned int status;
+	int ret;
+
+	/*
+	 * Setup required clock source, enable the corresponding
+	 * clock and channel and let work with continuous blink as
+	 * the default.
+	 */
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKCON1,
+				 MT6323_RG_ISINK_CK_SEL_MASK(led->id), 0);
+	if (ret < 0)
+		return ret;
+
+	status = MT6323_RG_ISINK_CK_PDN(led->id);
+	ret = regmap_update_bits(regmap, MT6323_TOP_CKPDN2,
+				 MT6323_RG_ISINK_CK_PDN_MASK(led->id),
+				 ~status);
+	if (ret < 0)
+		return ret;
+
+	usleep_range(100, 300);
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_EN_CTRL,
+				 MT6323_ISINK_CH_EN_MASK(led->id),
+				 MT6323_ISINK_CH_EN(led->id));
+	if (ret < 0)
+		return ret;
+
+	ret = mt6323_led_hw_brightness(cdev, brightness);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
+				 MT6323_ISINK_DIM_DUTY_MASK,
+				 MT6323_ISINK_DIM_DUTY(31));
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
+				 MT6323_ISINK_DIM_FSEL_MASK,
+				 MT6323_ISINK_DIM_FSEL(1000));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int mt6323_led_set_blink(struct led_classdev *cdev,
+				unsigned long *delay_on,
+				unsigned long *delay_off)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	struct regmap *regmap = leds->hw->regmap;
+	unsigned long period;
+	u8 duty_hw;
+	int ret;
+
+	/*
+	 * Units are in ms, if over the hardware able
+	 * to support, fallback into software blink
+	 */
+	period = *delay_on + *delay_off;
+
+	if (period > MT6323_MAX_PERIOD)
+		return -EINVAL;
+
+	/*
+	 * LED subsystem requires a default user
+	 * friendly blink pattern for the LED so using
+	 * 1Hz duty cycle 50% here if without specific
+	 * value delay_on and delay off being assigned.
+	 */
+	if (!*delay_on && !*delay_off) {
+		*delay_on = 500;
+		*delay_off = 500;
+	}
+
+	/*
+	 * Calculate duty_hw based on the percentage of period during
+	 * which the led is ON.
+	 */
+	duty_hw = MT6323_CAL_HW_DUTY(*delay_on, period);
+
+	/* hardware doesn't support zero duty cycle. */
+	if (!duty_hw)
+		return -EINVAL;
+
+	mutex_lock(&leds->lock);
+	/*
+	 * Set max_brightness as the software blink behavior
+	 * when no blink brightness.
+	 */
+	if (!led->current_brightness) {
+		ret = mt6323_led_hw_on(cdev, cdev->max_brightness);
+		if (ret < 0)
+			goto out;
+		led->current_brightness = cdev->max_brightness;
+	}
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON0(led->id),
+				 MT6323_ISINK_DIM_DUTY_MASK,
+				 MT6323_ISINK_DIM_DUTY(duty_hw - 1));
+	if (ret < 0)
+		goto out;
+
+	ret = regmap_update_bits(regmap, MT6323_ISINK_CON1(led->id),
+				 MT6323_ISINK_DIM_FSEL_MASK,
+				 MT6323_ISINK_DIM_FSEL(period - 1));
+out:
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int mt6323_led_set_brightness(struct led_classdev *cdev,
+				     enum led_brightness brightness)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	struct mt6323_leds *leds = led->parent;
+	int ret;
+
+	mutex_lock(&leds->lock);
+
+	if (!led->current_brightness && brightness) {
+		ret = mt6323_led_hw_on(cdev, brightness);
+		if (ret < 0)
+			goto out;
+	} else if (brightness) {
+		ret = mt6323_led_hw_brightness(cdev, brightness);
+		if (ret < 0)
+			goto out;
+	} else {
+		ret = mt6323_led_hw_off(cdev);
+		if (ret < 0)
+			goto out;
+	}
+
+	led->current_brightness = brightness;
+out:
+	mutex_unlock(&leds->lock);
+
+	return ret;
+}
+
+static int mt6323_led_set_dt_default(struct led_classdev *cdev,
+				     struct device_node *np)
+{
+	struct mt6323_led *led = container_of(cdev, struct mt6323_led, cdev);
+	const char *state;
+	int ret = 0;
+
+	led->cdev.name = of_get_property(np, "label", NULL) ? : np->name;
+	led->cdev.default_trigger = of_get_property(np,
+						    "linux,default-trigger",
+						    NULL);
+
+	state = of_get_property(np, "default-state", NULL);
+	if (state) {
+		if (!strcmp(state, "keep")) {
+			ret = mt6323_get_led_hw_brightness(cdev);
+			if (ret < 0)
+				return ret;
+			led->current_brightness = ret;
+			ret = 0;
+		} else if (!strcmp(state, "on")) {
+			ret =
+			mt6323_led_set_brightness(cdev, cdev->max_brightness);
+		} else  {
+			ret = mt6323_led_set_brightness(cdev, LED_OFF);
+		}
+	}
+
+	return ret;
+}
+
+static int mt6323_led_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = pdev->dev.of_node;
+	struct device_node *child;
+	struct mt6397_chip *hw = dev_get_drvdata(pdev->dev.parent);
+	struct mt6323_leds *leds;
+	struct mt6323_led *led;
+	int ret;
+	unsigned int status;
+	u32 reg;
+
+	leds = devm_kzalloc(dev, sizeof(*leds), GFP_KERNEL);
+	if (!leds)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, leds);
+	leds->dev = dev;
+
+	/*
+	 * leds->hw points to the underlying bus for the register
+	 * controlled.
+	 */
+	leds->hw = hw;
+	mutex_init(&leds->lock);
+
+	status = MT6323_RG_DRV_32K_CK_PDN;
+	ret = regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
+				 MT6323_RG_DRV_32K_CK_PDN_MASK, ~status);
+	if (ret < 0) {
+		dev_err(leds->dev,
+			"Failed to update MT6323_TOP_CKPDN0 Register\n");
+		return ret;
+	}
+
+	for_each_available_child_of_node(np, child) {
+		ret = of_property_read_u32(child, "reg", &reg);
+		if (ret) {
+			dev_err(dev, "Failed to read led 'reg' property\n");
+			goto put_child_node;
+		}
+
+		if (reg < 0 || reg > MT6323_MAX_LEDS || leds->led[reg]) {
+			dev_err(dev, "Invalid led reg %u\n", reg);
+			ret = -EINVAL;
+			goto put_child_node;
+		}
+
+		led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
+		if (!led) {
+			ret = -ENOMEM;
+			goto put_child_node;
+		}
+
+		leds->led[reg] = led;
+		leds->led[reg]->id = reg;
+		leds->led[reg]->cdev.max_brightness = MT6323_MAX_BRIGHTNESS;
+		leds->led[reg]->cdev.brightness_set_blocking =
+					mt6323_led_set_brightness;
+		leds->led[reg]->cdev.blink_set = mt6323_led_set_blink;
+		leds->led[reg]->cdev.brightness_get =
+					mt6323_get_led_hw_brightness;
+		leds->led[reg]->parent = leds;
+
+		ret = mt6323_led_set_dt_default(&leds->led[reg]->cdev, child);
+		if (ret < 0) {
+			dev_err(leds->dev,
+				"Failed to LED set default from devicetree\n");
+			goto put_child_node;
+		}
+
+		ret = devm_led_classdev_register(dev, &leds->led[reg]->cdev);
+		if (ret) {
+			dev_err(&pdev->dev, "Failed to register LED: %d\n",
+				ret);
+			goto put_child_node;
+		}
+		leds->led[reg]->cdev.dev->of_node = child;
+	}
+
+	return 0;
+
+put_child_node:
+	of_node_put(child);
+	return ret;
+}
+
+static int mt6323_led_remove(struct platform_device *pdev)
+{
+	struct mt6323_leds *leds = platform_get_drvdata(pdev);
+	int i;
+
+	/* Turn the LEDs off on driver removal. */
+	for (i = 0 ; leds->led[i] ; i++)
+		mt6323_led_hw_off(&leds->led[i]->cdev);
+
+	regmap_update_bits(leds->hw->regmap, MT6323_TOP_CKPDN0,
+			   MT6323_RG_DRV_32K_CK_PDN_MASK,
+			   MT6323_RG_DRV_32K_CK_PDN);
+
+	mutex_destroy(&leds->lock);
+
+	return 0;
+}
+
+static const struct of_device_id mt6323_led_dt_match[] = {
+	{ .compatible = "mediatek,mt6323-led" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mt6323_led_dt_match);
+
+static struct platform_driver mt6323_led_driver = {
+	.probe		= mt6323_led_probe,
+	.remove		= mt6323_led_remove,
+	.driver		= {
+		.name	= "mt6323-led",
+		.of_match_table = mt6323_led_dt_match,
+	},
+};
+
+module_platform_driver(mt6323_led_driver);
+
+MODULE_DESCRIPTION("LED driver for Mediatek MT6323 PMIC");
+MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
+MODULE_LICENSE("GPL");
